Screw and handle assembly



March 16, 1954 FIRTH 2,672,064

SCREW AND HANDLE ASSEMBLY Filed June 23 1950 INVENTOR.

Patented Mar. 16 1954 SCREW AND HANDLE ASSEMBLY David Firth, South Bend, Ind., assignor to Dodge Manufacturing Corporation, Mishawaka, Ind.,

a corporation of Indiana Application June 23, 1950, Serial No. 169,837

3 Claims. 1.

This invention relates to screw and handle assemblies for the clamping screws of vises and other screws to which the invention may be usefully applied.

The clamping screw of a bench vise, i. e. th screw-threaded shaft by which to force the vise jaws to relationship for clamping an interposed work piece, is ordinarily formed with a cylindrical head equipped with a handle consisting of a straight rod freely slidable through a transverse bore in the head and formed with motion-limiting knobs on its opposite ends. A vise is usually supported in such position that its clamping screw is horizontally disposed. When the handle rod is in a more or less vertical position, it normally hangs from the screw-head. The handle is used as a lever for rotating the screw. If it be swung from its hanging position through an angle of 180 degrees, more or less, and then released, it will drop by gravity from its upper position, sliding through the screw-head until the upper knob of the handle strikes the screw-head. If the operator should allow the handle rod to drop from an uppermost or near uppermost position while engaging the rod between his'thumb and forefinger, or while pressing a finger against either the front or a side of the rod, he would be likely to get a finger or. fingers pinched between the upper knob and the upper edge of the hole or bore in the screw-head. Sometimes painful blood blisters or abrasions or cuts of the skin are caused in this manner.

With a view to preventing or minimizing accidents of this nature, the present'invention pro- 7 vides a screw and handle assembly of the general character above indicated but-having the screw, head so formed in relation to the bore for the handle rod that the knobs thereof can strikethe head onlyat points adjacent to the back side of the rod, the knobs-in their innermost positions being substantially spaced from the head ,both at the front and opposite sides of the rod.

In the accompanying drawings, there is shown for example a simple form of vise having a screw and handle assembly embodying the invention.

Fig. 1 is a longitudinal section view of the illustrative vise.

Fig. 2 is a front elevation of the screw and handle assembly of the illustrative vise.

Fig. 3 is a side elevation of said assembly, omitting the major portion of the screw shaft.

Fig. 4 is a view similar to Fig. 3 showing the screw-head partly in section.

Figs. 5 and 6 are views corresponding to Figs. 3 and 4 showing a modified form of screw-head.

In Fig. 1, the movable and stationary jaw members of a vise are designated respectively by the numerals I and 2. As shown, the movable member is formed with a rearwardly extending shank 3 slidably fitted in a guide passage therefor in the stationary member, the base 4 of which is adapted to be secured on a work-bench or other support. The jaw members are operatively connected by a longitudinally disposed clamping screw 5 in the form of a headed screw-threaded shaft swiveled to the movable jaw member and in threaded engagement with the stationary jaw member. The enlarged head of the clamping screw, which head is designated as a whole by the numeral 6, abuts the front or outer face of the movable jaw member I. A collar 1 fixed on the screw shaft in abutting relation to the inner side of said member I cooperates with the screwhead 5 to prevent axial movement of the clamping screw relative to said member I. By rotating the clamping screw in a right hand direction, the movable jaw can be forced toward the fixed jaw for clamping an interposed work piece, and by rotatingsaid screw in a reverse direction the movable jaw can be moved away from the fixed jaw to release the work. Rotation of the clamping screw is effected by using as a lever a handle consisting of a straight round rod 8 freely slidably fitted in a bore therefor extending transversely through the screw-head 6, said rod being formed at its opposite ends with motion limiting knobs -9. r

As shown on a larger scale in Figs. 2 to 4, the screw-head 6 comprises a cylindrical body or portion It! formed with a forwardly extending tapered stub H. The cylindrical surface of the part In meets the tapered surface of said stub at the circle [2 (Fig. 3). The bore in which the handle rod slides is located substantially or nearly in said stub, the rearmost surface of said bore being about tangent to the plane of said circle-'- a condition to be considered fulfilled if the rear most surface of the bore be either exactly or approximately tangent to said plane or even slightly behind said plane. Preferably the rearmost'surface of the bore is tangent to said plane, but allowance must be made for minor inaccuracies tolerated in manufacture; moreover there would be no objection to locating the bore so that its rearmost surface is slightly behind said plane.

It will be apparent that the contour of the screw-head relative to the position of said bore is such that the handle knobs 9 can strike the head only at about diametrically opposite points adjacent to the back of the handle rod, i. e. at

points on or near the circle l2, and that the knobs in their innermost positions are substantially spaced from the stub H both at the front and opposite sides of the handle rod.

The stub H is tapered from the circle l2 to a fore portion ll of less diameter than that of said circle, said fore portion being of uniform diameter except that it terminates preferably in a beveled end H The surface of the tapered portion of the stub is concavecl or curved inwardly and forwardly from said circle and merges into the cylindrical surface of said fore portion H of said stub. The stub could be tapered for its full length; however the form of tapered stub shown is preferable to a conical stub,,-since it gives ample clearances at the front and opposite sides of the handle rod, between the stub and handle knobs in their innermost positions, without undesirably reducing the diameter of the fore end portion of the stub.

The screw .and handle assembly shown in Figs. 5 and 6 is the same as that already describedexcept for a modification in theforrn of the tapered stub. In this instance the screw-head, designated as a whole by the symbol 6, has its tapered stub I l formed with .an expanded fore "end portion H However, said expanded fore end .portion is located forward of a plane tangent to the handle knobs 9 and is of such form and dimen- :sions that the knobs .in their innermost positions are substantially spaced therefrom.

In an assembly of the type to which the invention relates, the object of the invention may be accomplished by forming in the periphery of the screw-head an annular groove concave in struction is exemplified in Figs.-5 andfi, and also in Figs. 2 to 4 except that in Figs. 2 and 4 the groove is a rabbet, being without a fore edge other than the fore edge of the tapered stub H.

The invention may be regarded as an improve- .ment in the vise to which it is applied, since .it permits operation of the clamping screw thereof by its handle without danger of getting the fin-- gers injured in the manner hereinbefore mentioned. It may be applied to vises of various types, including quickly adjustable vises of which an example is shown in patent to Zitner, .No. 2,464,630 of March 15, 1949. It'may also be of useful applicability to various other screws used or to be used in horizontally disposed position .for adjustment of the relationship of machinery parts or for jacking or other heavy duty purposes.

I claim:

1. An assembly comprising a screw having an enlarged head with a transverse bore extending therethrough and a handle consisting of a straight rod slidably fitted in said bore and equipped with motion-limiting knobs, said head comprising a cylindrical body formed with a for 'wardly extending stub, the peripheral surfaces of said body and stub having meeting edges defining a circle from which the surface of said stub .curves inwardly and forwardly, said bore being located in the stub with the rearmost surface of the bore about tangent to the plane of said circle, substantially as and for the purpose described.

'2. 'An'assembly comprising a screw having an enlargedhead with a transverse bore extending therethrough and a handle consisting of a straight rod slidably fitted in said bore and equipped with motion-llimiting knobs, said head having :a cylindrical portion and an inwardly tapered portion extending forwardly from cylindrical :portionand a fore portion extending from said tapered portion, the peripheral surfaces of said cylindrical and tapered portions having meeting edges defining a circle and said bore being so located that its rearinost surface isabout tangent to the plane of said circle, fore portion being of a diameter substantially less than that of said cylindrical portion, substantially-as and for the purpose described.

3. An :ass'embly comprising a screw having an enlarged head with a transverse bore extending therethrough and a handle consisting of a straight rod sli'dably fitted in said bore and equipped with motion-limiting knobs, said head having in its periphery an annular groove con- :cave in-crossesection and'of-a width substantiallygreater than the diameter of said bore and said bore being so locatedthat its ends are substantiallyinsaidgroove, the rear edge of said groove being in :a plane about tangent to the rearmost surface of said bore, the surface of the head immediately behind said edge being cylindrical, the surface -:of .said groove curving inwardly and forwardlytfrom said cylindrical surface, the front edge of said groove being substantially spaced .from said .rod and from the handle knobs in their innermost positions, substantially as and for the purpose described.

DAVID F TI-l.

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